1. Field of the Invention
The present invention relates to data terminal devices used in data distribution systems capable of protecting the copyright of copied information.
2. Description of the Background Art
In recent years the Internet and other similar information communication networks have advanced and a cellular phone or the like is used for a personal terminal to allow the user to readily access network information.
On such an information communication network a digital signal is used to transmit information. As such, if a user copies music, video data or the like transmitted on such an information communication network as described above, each individual user can copy such data almost free of significant degradation in the quality of sound, image and the like.
Thus, if music data, image data or other similar creations in copyright are transmitted on such an information communication network without any appropriate approach taken to protect the copyright, the copyright owner may have his/her right infringed significantly.
However, prioritizing copyright protection and preventing distribution of copyrighted data on a rapidly expanding digital information communication work, is disadvantageous to copyright owners, who basically can collect a predetermined copyright fee for copying copyrighted data.
In contrast, if digital data recorded in a recording medium, e.g., music data recorded in a normally sold compact disc (CD), is copied to a magneto-optical disk (such as an MD), it may be copied, as desired, as long as the copied data is solely for personal use, although an individual user who example digitally records data is required to indirectly pay as a bond to the copyright owner a predetermined portion of the price of the exact digital recording equipment, MD or any other similar media used by the user.
In addition, if music data in a digital signal is copied from a CD to an MD the information is digital data copied without significant degradation and accordingly equipment is configured to prevent copying music data from a recordable MD to another MD and thus protect copyright.
As such, distributing music data, image data and other similar data to the public on a digital information communication network is itself a behavior subject to a restriction attributed to a public transmission right of a copyright owner and a sufficient approach is accordingly required for protection of copyright.
Conventional cellular phones have a casing in the form of a shell. When the casing is closed, the current telephone call is disconnected and the cellular phone enters a low power consumption mode.
More specifically, with reference to FIG. 19, the cellular phone is powered off (step S1). Whether or not the power supply key has been pressed, is detected (step S2). If so then a liquid crystal display, a backlight and the like are turned on (step S3). If not then the control returns to step S1.
Then a standby status is conferred (step S4) and the control determines whether a call key has been pressed (step S5). If so then a call status is conferred (step S6). If not then the control moves on to step S10 to determine whether the casing in the form of the shell is open or closed.
During a call, the control determines whether a disconnection key has been pressed to disconnect the call (step S7). If so then the control returns to step S4.
If not then the control determines whether the casing has been closed (step S8). If not then the control returns to step S6.
If so the call is disconnected (step S9) and the cellular phone is conferred a standby status on with the casing closed (step S11). In the step S11 condition a low power supply consumption mode is set.
At step S10 if the control determines that the casing has been closed then the control moves on to step S11 and if the control determines that the casing is open then the control moves on to step S4.
In the step S11 condition, the control determines whether the casing is open or closed (step S12) and if the casing is closed then the control stays at step S11 and if the casing is opened then the control moves on to step S3.
In other words, to continue a call (including mails, communications via personal computers, and the like) the conventional cellular phone in the form of a shell must have its casing in the form of the shell kept open.
Conventional cellular phones in the form of a shell cannot download or reproduce encrypted content data with a copyright sufficiently protected, a license key and the like. If the encrypted content data, the license key and the like are configured to be downloaded and reproducible, the cellular phone still needs to have its casing in the form of the shell kept open while it downloads or reproduces the data, the key and the like. Such is particularly inconvenient if a large amount of data such as music content is downloaded and reproduced as the casing needs to be kept open for a long period of time.